MECHANISM OF ADHERENCE: Our results have shown that the a-d cell wall antigen polysaccharide and dextran of S. mutans function as binding sites for dextran-levan sucrases, and that adherence to glass of the streptococci resulted when polymer synthesis on the surface of the cell occurred. Antibody to each prevented the binding and adherence. We propose to obtain further proof of the binding site function of the a-d polysaccharide antigen and dextran. PROPOSED RESEARCH: (1) esterification of cell wall polysaccharide antigen of S. mutans (12, 13, 16), attachment of ester to surface of red blood cell, and use of this cell as a site for binding of sucrase enzymes, dextran synthesis and adherence. This technique should enable the complete process to occur free of the S. mutans cell. (2) function of a-d antigen in the group d S. mutans polysaccharide as a binding site for enzyme, polymer synthesis and adherence. (3) the c antigen of S. mutans and its function in adherence. (4) immunological relationship of sucrase enzymes from the serological groups of S. mutans.